SGS Thomson Microelectronics L4957AV3.3, L4957AV2.5, L4957AV1.8, L4957AV1.5, L4957AD2.5 Datasheet
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L4957A
UP TO 5A ULDO LINEAR REGULATOR
PRODUCT PREVIEW
1.5V, 1.8V, 2.5V AND 3.3V FIXED OUTPUT
VOLTAGE
3V TO 14V INPUT VOLTAGERANGE
200mΩ RdsonTYPICAL @ T
j = 125°C
0.6V max. DROP-OUT AT 2A
EXCELLENTLOAD REGULATION
0.6mAQUIESCENTCURRENT AT ANYLOAD
SHORTCIRCUIT PROTECTION
THERMAL SHUTDOWN
APPLICATIONS
MOTHERBOARDS
PROCESSORI/O& SUPPLIES
LOW VOLTAGE MEMORY & CHIP SET SUP-
PLIES
GRAPHIC& SOUND CARDS
LOW VOLTAGELOGIC SUPPLIES
POST REGULATORFOR SMPS
DESCRIPTION
The L4957A devices are Ultra Low Drop Output
linear regulators with an internal N-channel MOS
of 200mΩ particulary suitable for low voltage/low
dropoutapplications.
Operating with a input voltage from 3V to 14V
they are capableto deliver up to5A.
The devices are ideal for use as one of the sup-
MULTIPOWER BCD TECHNOLOGY
3
1
D2PAKVersawatt TO-220
ORDERING NUMBERS:
L4957AV1.5 L4957AD1.5
L4957AV1.8 L4957AD1.8
L4957AV2.5 L4957AD2.5
L4957AV3.3 L4957AD3.3
plies required by processor, for example they are
the cost effective and efficient solution for conversion from 3.3V (rail bus) to 2.5V @ 2.5A or to
1.5Vwith highcurrent rating.
Fast response transient minimise the output ca-
pacitor value. A minimum of 22µF assures the
stabilityin all load conditions.
The on-chip trimming technique offers a tighter
voltage reference tolerance (with ±
2% including
line and load variation) beside to ensure a controlled short circuit current. Thermal shutdown
provides protection against overload conditions
that creates excessivejunction temperature.
TYPICAL APPLICATION
3V to 14V
OUTIN
1
3
V
OUT
L4957A
C1
May 2000
This is preliminary information on a new product now in development. Details are subject to change without notice.
2
GND
D00IN1107A
C2
1/7
L4957A
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
IN
T
i
T
stg
PINSCONNECTION
SupplyInput Voltage 16 V
JunctionTemperature -40 to +150 °C
Storage Temperature -40 to +150 °C
Versawatt (TO220)
BLOCKDIAGRAM
V
IN
10µF
IN
1
3
2
1
PRE
REGULATOR
D98IN838B
V
REF
+
E/A
-
OUT
GND
IN
CURRENT
LIMIT
CHARGE
PUMP
BUFFER
THERMAL
SHUTDOWN
3
2
1
D2PAK
POWER
DMOS
200mΩ
R
X
GND
3
OUT
IN
D98IN933A
OUT
V
22µF
OUT
R
Y
2
GND
D00IN1108A
PIN FUNCTIONS
Pin N° Name Function
1 IN Unregulated input voltage; this pin must be bypassed with acapacitor larger than 10µF.
2 GND To connect to Ground to get 1.5V, 1.8V, 2.5V or 3.3V output.
3 OUT Regulated output voltage. A minimum bypass capacitor of 22µF is required to insurestability.
2/7
THERMALDATA
Symbol Parameter TO220 D2PAK Unit
R
th j-case
R
th j-amb
Thermal Resistance Junction-case Max. 2.5 3 °C/W
Thermal Resistance Junction-ambient Max. 50 60 °C/W
Thermal Shutdown Typ. 150 °C
Thermal Hysteresis Typ. 20 °C
ELECTRICAL CHARACTERISTICS (Tj=25°C, VIN= 5V, unlessotherwise specified).
•
= Specificationsreferred to TJfrom 0°Cto +125°C.
Symbol Parameter Test Condition Min. Typ. Max. Unit
V
IN
V
O
DSON Drain-Source ON
R
I
O
I
Q
OperatingSupply Voltage 3 14 V
Output Voltage 3.15V < VIN< 5.25V;IO=0.1A 1.485 1.5 1.515 V
=3.3V±5%;0.1A< I
V
IN
=3.3V ±5% IO= 0.1A
V
IN
V
=5V±5%
IN
=3.3V ±5% (0.1A< IO< 45A)
V
IN
V
=5V±5% 0.1A< IO<5A
IN
V
=3.3V ±5% IO= 0.1A
IN
V
=5V±5%
IN
=3.3V ±5% (0.1A< IO<2.2A)
V
IN
V
=5V±5% 0.1A< IO<5A
IN
V
=5V±5% IO= 0.1A 3.267 3.3 3.333 V
IN
=5V±5% 0.1A< I
V
IN
<5A • 1.47 1.5 1.53 V
O
1.782 1.8 1.818 V
•
1.764 1.8 1.836 V
2.475 2.5 2.525 V
•
2.45 2.5 2.55 V
<5A • 3.234 3.3 3.366 V
O
•
300 mΩ
Resistance
Current Limiting • 5.1 6.3 7.5 A
Quiescent Current 3V < V
Ripple Rejection f = 120Hz, I
V
< 14V • 0.6 2 mA
IN
=1A
=5V∆VIN=2V
IN
O
PP
60 75 dB
L4957A
Figure1: Line Regulation vs. Junction
Temperature
5
4.5
4
3.5
3
2.5
2
Output Voltage Deviation [mV]
1.5
1
0.5
0
-40 -20 0 20 40 60 80 100 120 140 160
3V < Vin < 6.5V
Iout = 10mA
Tj[°C]
Figure2: Load Regulation
5
4
3
2
1
0
Output Voltage Deviation [mV]
-1
-2
-3
-4
-5
012345
(Pulsed technique has been used)
Vin = 5V
Tj = 25 °C
Vout= 1.5V
Iout [A]
3/7
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